import java.util.Arrays;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * user:likai
 * Date:2022-10-05
 * Time:11:38
 */
class Solution{
    public String toLowerCase(String s){
        StringBuilder stringBuilder=new StringBuilder();
        for (int i = 0; i < s.length(); i++) {
            char ret=s.charAt(i);
            if(ret>='A'&&ret<='Z'){
                stringBuilder.append((char)(ret-32));
            }else{
                stringBuilder.append(ret);
            }
        }
        return stringBuilder.toString();
    }
}
public class Test {

    public static void main(String[] args) {
        String string="a c";
        String []ret=string.split(" ");
        System.out.println(Arrays.toString(ret));
        System.out.println(ret.length);
    }
}
